The present invention relates to industrial containers or drums and, more particularly, to containers of the type that are desirably salvaged, reconditioned and reused.
In the construction of large metal drums a cylindrical shell is joined by a seam to an end closure. Various constructional methods have been employed heretofore in the fabrication of such drums. A common method is to produce a cylindrical shell with radial flanges at its ends to which is assembled a radially flanged end closure whereupon the mating parts are rolled or curled to form a seam. It is also known to form such containers by starting with an unflanged cylindrical shell to which an end closure is assembled whereupon the mating parts are rolled and formed to produce the seam.
Under certain conditions it becomes economically attractive to be able to salvage the principle components of the drum or container after use, to recondition the parts and provide for a reusable container.
One technique for reconditioning a container is described in U.S. Pat. No. 3,922,984 issued Dec. 2, 1975. The container described in said patent has a radially outwardly projecting spiral seam formed by an end wall and body wall of the container which seam is unrolled by a tool that embraces the shell and moves in the longitudinal direction of the shell relative thereto. Various other methods for reconditioning containers are summarized in said patent but none is entirely satisfactory.